Andrew McCarthy is a senior fellow at the National Review Institute. He was an Assistant U.S. Attorney in the Southern District of New York for 18 years, and led the terrorism prosecution against Sheik Omar Abdel Rahman and 11 others in connection with the 1993 World Trade Center bombing.

The following is adapted from a speech he delivered at Hillsdale College.

“In 1993 I was a seasoned federal prosecutor, but I only knew as much about Islam as the average American with a reasonably good education—which is to say, not much. Consequently, when I was assigned to lead the prosecution of a terrorist cell that had bombed the World Trade Center and was plotting an even more devastating, simultaneous attacks on the London and Holland Tunnels, the United Nations, and the FBI’s lower Manhattan headquarters—I had no trouble believing what our government was saying: that we should read nothing into the fact that all the men in this terrorist cell were Muslims; that their actions were not representative of any religion or belief system; and that to the extent they were explaining their atrocities by citing Islamic scripture, they were twisting and perverting one of the world’s great religions, a religion that encourages peace.

“Prosecutors don’t get to base their cases on assertions. They have to prove things to commonsense Americans who must be satisfied about not only what happened but why it happened before they will convict people of serious crimes. And in examining the government’s claims, I found them false.

One of the first things I learned concerned the leader of the terror cell, Omar Abdel Rahman, infamously known as the Blind Sheikh. Our government was portraying him as a wanton killer who was lying about Islam by preaching that it summoned Muslims to jihad or holy war. Far from a lunatic, however, he turned out to be a globally renowned scholar—a doctor of Islamic jurisprudence.

“I immediately began to wonder why American officials from President Clinton and Attorney General Janet Reno on down, officials who had no background in Muslim doctrine and culture, believed they knew more about Islam than the Blind Sheikh.

“Defendants do not have to testify at criminal trials, but they have a right to testify if they choose to—so I had to prepare for the possibility. Raised an Irish Catholic in the Bronx, I was not foolish enough to believe I could win an argument over Muslim theology with a doctor of Islamic jurisprudence. But I did think that if what we were saying as a government were true—that he was perverting Islam—than there must be two or three places where I could nail him by saying, ‘You told your followers X, but the doctrine clearly says Y.’ So my colleagues and I pored over the Blind Sheikh’s writings. What we found was alarming; whenever he quoted the Koran or other sources of Islamic scripture, he quoted them accurately.

“Now, you might be able to argue that he took scripture out of context or gave an incomplete account of it. In my subsequent years of studying Islam, I’ve learned that this is not a particularly persuasive argument. But even if one concedes for the purposes of discussion that it’s a colorable claim, the inconvenient fact remains: Abdel Rahman was not lying about Islam.

“When he said the scriptures command that Muslims strike terror into the hearts of Islam’s enemies, the scriptures backed him up.

“When he said Allah enjoined all Muslims to wage jihad until Islamic law was established throughout the world, the scriptures backed him up.

“When he said Islam directed Muslims not to take Jews and Christians as their friends, the scriptures backed him up.

“You could counter that there are other ways of construing the scriptures. You could contend that these exhortations to violence and hatred should be ‘contextualized’—i.e., that they were only meant for their time and place in the seventh century. Again, I would caution that there are compelling arguments against this manner of interpreting Islamic scripture. The point, however, is that what you’d be arguing is an interpretation.

“The fact that there are multiple ways of construing Islam hardly makes the Blind Sheikh’s literal construction wrong. The blunt fact of the matter is that, in this contest of competing interpretations, it is the jihadists who seem to be making sense because they have the words of scripture on their side—it is the others who seem to be dancing on the head of a pin. For our present purposes, however, the fact is that the Blind Sheikh’s summons to jihad was rooted in a coherent interpretation of Islamic doctrine. He was not perverting Islam—he was, if anything, shining a light on the need to reform it.

“Another point, obvious but inconvenient, is that Islam is not a religion of peace. There are ways of interpreting Islam that could make it something other than a call to war. But even these benign constructions do not make it a call to peace. Verses such as ‘Fight those who believe not in Allah,’ and ‘Fight and slay the pagans wherever ye find them, and seize them, beleaguer them, and lie in wait for them in every stratagem of war,’ are not peaceful injunctions, no matter how one contextualizes.

“Now, understand: there was no doubt what the Blind Sheikh was on trial for. And there was no doubt that he was a terrorist—after all, he bragged about it. But that did not disqualify him, in the minds of these moderate, peaceful Muslims, from rendering authoritative opinions on the meaning of the core tenets of their religion. No one was saying that they would follow the Blind Sheikh into terrorism—but no one was discrediting his status either.

“Habitually, I distinguish between Islam and Muslims. It is objectively important to do so, but I also have a personal reason: when I began working on national security cases, the Muslims I first encountered were not terrorists. To the contrary, they were pro-American patriots who helped us infiltrate terror cells, disrupt mass-murder plots, and gather the evidence needed to convict jihadists. We have an obligation to our national security to understand our enemies; but we also have an obligation to our principles not to convict by association—not to confound our Islamist enemies with our Muslim allies and fellow citizens.

“What about Islamic law? On this topic, it is useful to turn to Robert Jackson, a giant figure in American law and politics—FDR’s attorney general, justice of the Supreme Court, and chief prosecutor of the war crimes trials at Nuremberg. In 1955, Justice Jackson penned the foreword to a book called Law in the Middle East. Unlike today’s government officials, Justice Jackson thought sharia was a subject worthy of close study. And here is what he concluded:

“‘In any broad sense, Islamic law offers the American lawyer a study in dramatic contrasts. Even casual acquaintance and superficial knowledge—all that most of us at bench or bar will be able to acquire—reveal that its striking features relative to our law are not likenesses but inconsistencies, not similarities but contrarieties. In its source, its scope and its sanctions, the law of the Middle East is the antithesis of Western law.’

“Sharia law rejects freedom of speech as much as freedom of religion. It rejects the idea of equal rights between men and women as much as between Muslim and non-Muslim. It brooks no separation between spiritual life and civil society. It is a comprehensive framework for human life, dictating matters of government, economy, and combat, along with personal behavior such as contact between the sexes and personal hygiene. Sharia aims to rule both believers and non-believers, and it affirmatively sanctions jihad in order to do so.

“Even if this is not the only construction of Islam, it is absurd to claim—as President Obama did during his recent visit to a mosque in Baltimore—that it is not a mainstream interpretation. In fact, it is the mainstream interpretation in many parts of the world. Last year, Americans were horrified by the beheadings of three Western journalists by ISIS. American and European politicians could not get to microphones fast enough to insist that these decapitations had nothing to do with Islam. Yet within the same time frame, the government of Saudi Arabia beheaded eight people for various violations of sharia—the law that governs Saudi Arabia.

“This is political correctness on steroids, and it has dangerous policy implications. Consider the inability of government officials to call a mass-murder attack by Muslims a terrorist attack unless and until the police uncover evidence proving that the mass murderers have some tie to a designated terrorist group, such as ISIS or al Qaeda. It is rare for such evidence to be uncovered early in an investigation—and as a matter of fact, such evidence often does not exist. Terrorist recruits already share the same ideology as these groups: the goal of imposing sharia. All they need in order to execute terrorist attacks is paramilitary training, which is readily available in more places than just Syria.

“The dangerous flipside to our government’s insistence on making up its own version of Islam is that anyone who is publicly associated with Islam must be deemed peaceful. This is how we fall into the trap of allowing the Muslim Brotherhood, the world’s most influential Islamic supremacist organization, to infiltrate policy-making organs of the U.S. government, not to mention our schools, our prisons, and other institutions. The federal government acknowledges the Brotherhood as an Islamic organization—notwithstanding the ham-handed attempt by the intelligence community a few years back to rebrand it as “largely secular”—thereby giving it a clean bill of health. This despite the fact that Hamas is the Brotherhood’s Palestinian branch, that the Brotherhood has a long history of terrorist violence, and that major Brotherhood figures have gone on to play leading roles in terrorist organizations such as al Qaeda.

“To quote Winston Churchill: ‘Facts are better than dreams.’ In the real world, we must deal with the facts of Islamic supremacism, because its jihadist legions have every intention of dealing with us. But we can only defeat them if we resolve to see them for what they are.”